1. Field of the Invention
The present invention generally relates to a bandpass filter, a high frequency module using the bandpass filter, and a radio communication device using the bandpass filter and the high frequency module, and more particularly, relates to a bandpass filter that may be preferably used for UWB (Ultra Wide Band) and has a very broad pass band, a high frequency module using the bandpass filter, and a radio communication device using the bandpass filter and the high frequency module.
2. Description of the Related Art
In recent years, UWB (Ultra Wide Band) has drawn attention as a new communication means. UWB transmits huge amounts of data using a broad frequency band over a short distance such as 10 m, and for example, a frequency band of 3.1 to 10.6 GHz is subjected to use for UWB according to the rule of U.S. FCC (Federal Communication Commission). As such, a feature of UWB is to utilize a very broad frequency band. Japan and the ITU-R have a plan to introduce standards separated into a low band of about 3.1 to 4.7 GHz and a high band of about 6 GHz to 10.6 GHz to avoid a band of 5.3 GHz that is used in the IEEE802.11a standard. Accordingly, a low band filter requires the characteristic of being abruptly attenuated at 2.5 GHz and 5.3 GHz.